I had the same problem with approx same mileage on my 1992 300CE and turned out to be the EZL. Replaced and no more problems. Sometimes you can find them on Ebay but you have to cross-reference your cars VIN number with the numbers on the EZL. The problem is it can be dicey to buy an electrical part on line and so I went to the dealer. Cost at the dealer is about $1200 with my Mercedes Benz membership discount.

I happen to have it after the car crashed. It has about <10K on it and have the paperwork to prove it. Only if you are interested.

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Norm K.
'97 E420 Sport
'06 E350 Sedan
'67 Mustang Coupe
'70 F-250
'15 VW Jetta